The tpm-rng.c approach is completely inconsistent with how the kernel
handles hotplug. Instead manage a hwrng device for each TPM. This will
cause the kernel to read entropy from the TPM when it is plugged in,
and allow access to the TPM rng via /dev/hwrng.
Signed-off-by: PrasannaKumar Muralidharan <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
---
drivers/char/hw_random/Kconfig | 13 -----------
drivers/char/hw_random/Makefile | 1 -
drivers/char/hw_random/tpm-rng.c | 50 ----------------------------------------
drivers/char/tpm/Kconfig | 13 +++++++++++
drivers/char/tpm/tpm-chip.c | 41 ++++++++++++++++++++++++++++----
drivers/char/tpm/tpm-interface.c | 37 ++++++++++++++++-------------
drivers/char/tpm/tpm.h | 5 ++++
7 files changed, 76 insertions(+), 84 deletions(-)
delete mode 100644 drivers/char/hw_random/tpm-rng.c
All,
It is such a good idea, I took PrasannaKumar's patch, reviewed and
revised it to the level it could be merged.
This is compile tested only.
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 95a031e9eced07..a20fed182cbcce 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -306,19 +306,6 @@ config HW_RANDOM_POWERNV
If unsure, say Y.
-config HW_RANDOM_TPM
- tristate "TPM HW Random Number Generator support"
- depends on TCG_TPM
- default HW_RANDOM
- ---help---
- This driver provides kernel-side support for the Random Number
- Generator in the Trusted Platform Module
-
- To compile this driver as a module, choose M here: the
- module will be called tpm-rng.
-
- If unsure, say Y.
-
config HW_RANDOM_HISI
tristate "Hisilicon Random Number Generator support"
depends on HW_RANDOM && ARCH_HISI
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 39a67defac67cb..91cb8e8213e7c1 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -26,7 +26,6 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
obj-$(CONFIG_HW_RANDOM_HISI) += hisi-rng.o
-obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o
diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c
deleted file mode 100644
index d6d448266f0752..00000000000000
--- a/drivers/char/hw_random/tpm-rng.c
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Copyright (C) 2012 Kent Yoder IBM Corporation
- *
- * HWRNG interfaces to pull RNG data from a TPM
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-#include <linux/module.h>
-#include <linux/hw_random.h>
-#include <linux/tpm.h>
-
-#define MODULE_NAME "tpm-rng"
-
-static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
-{
- return tpm_get_random(TPM_ANY_NUM, data, max);
-}
-
-static struct hwrng tpm_rng = {
- .name = MODULE_NAME,
- .read = tpm_rng_read,
-};
-
-static int __init rng_init(void)
-{
- return hwrng_register(&tpm_rng);
-}
-module_init(rng_init);
-
-static void __exit rng_exit(void)
-{
- hwrng_unregister(&tpm_rng);
-}
-module_exit(rng_exit);
-
-MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Kent Yoder <[email protected]>");
-MODULE_DESCRIPTION("RNG driver for TPM devices");
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index a30352202f1fdc..a95725fa77789e 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -26,6 +26,19 @@ menuconfig TCG_TPM
if TCG_TPM
+config HW_RANDOM_TPM
+ tristate "TPM HW Random Number Generator support"
+ depends on TCG_TPM && HW_RANDOM
+ default HW_RANDOM
+ ---help---
+ This driver provides kernel-side support for the Random Number
+ Generator in the Trusted Platform Module
+
+ To compile this driver as a module, choose M here: the
+ module will be called tpm-rng.
+
+ If unsure, say Y.
+
config TCG_TIS_CORE
tristate
---help---
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 0eca20c5a80cf2..f3571406fb2995 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -26,6 +26,7 @@
#include <linux/spinlock.h>
#include <linux/freezer.h>
#include <linux/major.h>
+#include <linux/hw_random.h>
#include "tpm.h"
#include "tpm_eventlog.h"
@@ -387,6 +388,26 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
return 0;
}
+
+static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+ struct tpm_chip *chip = container_of(rng, struct tpm_chip, tpm_hwrng);
+
+ return tpm_get_random_dev(chip, data, max);
+}
+
+static int tpm_add_hwrng(struct tpm_chip *chip)
+{
+ if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
+ return 0;
+
+ snprintf(chip->tpm_hwrng_name, sizeof(chip->tpm_hwrng_name),
+ "tpm-rng-%d", chip->dev_num);
+ chip->tpm_hwrng.name = chip->tpm_hwrng_name;
+ chip->tpm_hwrng.read = tpm_hwrng_read;
+ return hwrng_register(&chip->tpm_hwrng);
+}
+
/*
* tpm_chip_register() - create a character device for the TPM chip
* @chip: TPM chip to use.
@@ -419,11 +440,13 @@ int tpm_chip_register(struct tpm_chip *chip)
tpm_add_ppi(chip);
+ rc = tpm_add_hwrng(chip);
+ if (rc)
+ goto out_ppi;
+
rc = tpm_add_char_device(chip);
- if (rc) {
- tpm_bios_log_teardown(chip);
- return rc;
- }
+ if (rc)
+ goto out_hwrng;
rc = tpm_add_legacy_sysfs(chip);
if (rc) {
@@ -432,6 +455,14 @@ int tpm_chip_register(struct tpm_chip *chip)
}
return 0;
+
+out_hwrng:
+ if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
+ hwrng_unregister(&chip->tpm_hwrng);
+out_ppi:
+ tpm_bios_log_teardown(chip);
+
+ return rc;
}
EXPORT_SYMBOL_GPL(tpm_chip_register);
@@ -451,6 +482,8 @@ EXPORT_SYMBOL_GPL(tpm_chip_register);
void tpm_chip_unregister(struct tpm_chip *chip)
{
tpm_del_legacy_sysfs(chip);
+ if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
+ hwrng_unregister(&chip->tpm_hwrng);
tpm_bios_log_teardown(chip);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
cdev_device_del(&chip->cdevs, &chip->devs);
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1d6729be4cd637..310de288549818 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1194,9 +1194,8 @@ static const struct tpm_input_header tpm_getrandom_header = {
*
* Returns < 0 on error and the number of bytes read on success
*/
-int tpm_get_random(u32 chip_num, u8 *out, size_t max)
+int tpm_get_random_dev(struct tpm_chip *chip, u8 *out, size_t max)
{
- struct tpm_chip *chip;
struct tpm_cmd_t tpm_cmd;
u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA), rlength;
int err, total = 0, retries = 5;
@@ -1205,15 +1204,8 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
return -EINVAL;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
- return -ENODEV;
-
- if (chip->flags & TPM_CHIP_FLAG_TPM2) {
- err = tpm2_get_random(chip, out, max);
- tpm_put_ops(chip);
- return err;
- }
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ return tpm2_get_random(chip, out, max);
do {
tpm_cmd.header.in = tpm_getrandom_header;
@@ -1231,10 +1223,9 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
rlength = be32_to_cpu(tpm_cmd.header.out.length);
if (rlength < offsetof(struct tpm_getrandom_out, rng_data) +
- recd) {
- total = -EFAULT;
- break;
- }
+ recd)
+ return -EFAULT;
+
memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd);
dest += recd;
@@ -1242,9 +1233,23 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
num_bytes -= recd;
} while (retries-- && total < max);
- tpm_put_ops(chip);
return total ? total : -EIO;
}
+
+int tpm_get_random(u32 chip_num, u8 *out, size_t max)
+{
+ int rc;
+ struct tpm_chip *chip;
+
+ chip = tpm_chip_find_get(chip_num);
+ if (chip == NULL)
+ return -ENODEV;
+
+ rc = tpm_get_random_dev(chip, out, max);
+
+ tpm_put_ops(chip);
+ return rc;
+}
EXPORT_SYMBOL_GPL(tpm_get_random);
/**
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 2d5466a72e40f8..0e41e044d81be2 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -26,6 +26,7 @@
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/fs.h>
+#include <linux/hw_random.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/platform_device.h>
@@ -210,6 +211,9 @@ struct tpm_chip {
int dev_num; /* /dev/tpm# */
unsigned long is_open; /* only one allowed */
+ char tpm_hwrng_name[64];
+ struct hwrng tpm_hwrng;
+
struct mutex tpm_mutex; /* tpm is processing */
unsigned long timeout_a; /* jiffies */
@@ -548,6 +552,7 @@ void tpm_chip_unregister(struct tpm_chip *chip);
void tpm_sysfs_add_device(struct tpm_chip *chip);
int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
+int tpm_get_random_dev(struct tpm_chip *chip, u8 *out, size_t max);
#ifdef CONFIG_ACPI
extern void tpm_add_ppi(struct tpm_chip *chip);
--
2.7.4
On Tue, Oct 24, 2017 at 12:42:35PM -0600, Jason Gunthorpe wrote:
> This is compile tested only.
0day says the kconfig has a problem when randomized, here is the fix I
will roll into a v2 in a few days:
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index a95725fa77789e..ca89da3e4b2ae9 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -27,16 +27,13 @@ menuconfig TCG_TPM
if TCG_TPM
config HW_RANDOM_TPM
- tristate "TPM HW Random Number Generator support"
- depends on TCG_TPM && HW_RANDOM
- default HW_RANDOM
+ bool "TPM HW Random Number Generator support"
+ depends on TCG_TPM && HW_RANDOM && !(TCG_TPM=y && HW_RANDOM=m)
+ default y
---help---
This driver provides kernel-side support for the Random Number
Generator in the Trusted Platform Module
- To compile this driver as a module, choose M here: the
- module will be called tpm-rng.
-
If unsure, say Y.
config TCG_TIS_CORE
On Tue, Oct 24, 2017 at 03:34:49PM -0600, Jason Gunthorpe wrote:
> On Tue, Oct 24, 2017 at 12:42:35PM -0600, Jason Gunthorpe wrote:
>
> > This is compile tested only.
>
> 0day says the kconfig has a problem when randomized, here is the fix I
> will roll into a v2 in a few days:
I will probably have to postpone the review to next week anyway so take
your time :-)
/Jarkko
>
> diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
> index a95725fa77789e..ca89da3e4b2ae9 100644
> --- a/drivers/char/tpm/Kconfig
> +++ b/drivers/char/tpm/Kconfig
> @@ -27,16 +27,13 @@ menuconfig TCG_TPM
> if TCG_TPM
>
> config HW_RANDOM_TPM
> - tristate "TPM HW Random Number Generator support"
> - depends on TCG_TPM && HW_RANDOM
> - default HW_RANDOM
> + bool "TPM HW Random Number Generator support"
> + depends on TCG_TPM && HW_RANDOM && !(TCG_TPM=y && HW_RANDOM=m)
> + default y
> ---help---
> This driver provides kernel-side support for the Random Number
> Generator in the Trusted Platform Module
>
> - To compile this driver as a module, choose M here: the
> - module will be called tpm-rng.
> -
> If unsure, say Y.
>
> config TCG_TIS_CORE
Hi Jason,
Nice to see this patch. Some minor comments below.
On 25 October 2017 at 00:12, Jason Gunthorpe
<[email protected]> wrote:
> The tpm-rng.c approach is completely inconsistent with how the kernel
> handles hotplug. Instead manage a hwrng device for each TPM. This will
> cause the kernel to read entropy from the TPM when it is plugged in,
> and allow access to the TPM rng via /dev/hwrng.
>
> Signed-off-by: PrasannaKumar Muralidharan <[email protected]>
> Signed-off-by: Jason Gunthorpe <[email protected]>
> Reviewed-by: Jason Gunthorpe <[email protected]>
> ---
> drivers/char/hw_random/Kconfig | 13 -----------
> drivers/char/hw_random/Makefile | 1 -
> drivers/char/hw_random/tpm-rng.c | 50 ----------------------------------------
> drivers/char/tpm/Kconfig | 13 +++++++++++
> drivers/char/tpm/tpm-chip.c | 41 ++++++++++++++++++++++++++++----
> drivers/char/tpm/tpm-interface.c | 37 ++++++++++++++++-------------
> drivers/char/tpm/tpm.h | 5 ++++
> 7 files changed, 76 insertions(+), 84 deletions(-)
> delete mode 100644 drivers/char/hw_random/tpm-rng.c
>
> All,
>
> It is such a good idea, I took PrasannaKumar's patch, reviewed and
> revised it to the level it could be merged.
Thank you for this.
> This is compile tested only.
>
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index 95a031e9eced07..a20fed182cbcce 100644
> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -306,19 +306,6 @@ config HW_RANDOM_POWERNV
>
> If unsure, say Y.
>
> -config HW_RANDOM_TPM
> - tristate "TPM HW Random Number Generator support"
> - depends on TCG_TPM
> - default HW_RANDOM
> - ---help---
> - This driver provides kernel-side support for the Random Number
> - Generator in the Trusted Platform Module
> -
> - To compile this driver as a module, choose M here: the
> - module will be called tpm-rng.
> -
> - If unsure, say Y.
> -
> config HW_RANDOM_HISI
> tristate "Hisilicon Random Number Generator support"
> depends on HW_RANDOM && ARCH_HISI
> diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
> index 39a67defac67cb..91cb8e8213e7c1 100644
> --- a/drivers/char/hw_random/Makefile
> +++ b/drivers/char/hw_random/Makefile
> @@ -26,7 +26,6 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
> obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
> obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
> obj-$(CONFIG_HW_RANDOM_HISI) += hisi-rng.o
> -obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
> obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
> obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
> obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o
> diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c
> deleted file mode 100644
> index d6d448266f0752..00000000000000
> --- a/drivers/char/hw_random/tpm-rng.c
> +++ /dev/null
> @@ -1,50 +0,0 @@
> -/*
> - * Copyright (C) 2012 Kent Yoder IBM Corporation
> - *
> - * HWRNG interfaces to pull RNG data from a TPM
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License version 2 as
> - * published by the Free Software Foundation.
> - *
> - * This program is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> - * GNU General Public License for more details.
> - *
> - * You should have received a copy of the GNU General Public License
> - * along with this program; if not, write to the Free Software
> - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> - */
> -
> -#include <linux/module.h>
> -#include <linux/hw_random.h>
> -#include <linux/tpm.h>
> -
> -#define MODULE_NAME "tpm-rng"
> -
> -static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
> -{
> - return tpm_get_random(TPM_ANY_NUM, data, max);
> -}
> -
> -static struct hwrng tpm_rng = {
> - .name = MODULE_NAME,
> - .read = tpm_rng_read,
> -};
> -
> -static int __init rng_init(void)
> -{
> - return hwrng_register(&tpm_rng);
> -}
> -module_init(rng_init);
> -
> -static void __exit rng_exit(void)
> -{
> - hwrng_unregister(&tpm_rng);
> -}
> -module_exit(rng_exit);
> -
> -MODULE_LICENSE("GPL v2");
> -MODULE_AUTHOR("Kent Yoder <[email protected]>");
> -MODULE_DESCRIPTION("RNG driver for TPM devices");
> diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
> index a30352202f1fdc..a95725fa77789e 100644
> --- a/drivers/char/tpm/Kconfig
> +++ b/drivers/char/tpm/Kconfig
> @@ -26,6 +26,19 @@ menuconfig TCG_TPM
>
> if TCG_TPM
>
> +config HW_RANDOM_TPM
> + tristate "TPM HW Random Number Generator support"
> + depends on TCG_TPM && HW_RANDOM
> + default HW_RANDOM
> + ---help---
> + This driver provides kernel-side support for the Random Number
> + Generator in the Trusted Platform Module
> +
> + To compile this driver as a module, choose M here: the
> + module will be called tpm-rng.
> +
> + If unsure, say Y.
> +
> config TCG_TIS_CORE
> tristate
> ---help---
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 0eca20c5a80cf2..f3571406fb2995 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -26,6 +26,7 @@
> #include <linux/spinlock.h>
> #include <linux/freezer.h>
> #include <linux/major.h>
> +#include <linux/hw_random.h>
> #include "tpm.h"
> #include "tpm_eventlog.h"
>
> @@ -387,6 +388,26 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
>
> return 0;
> }
> +
> +static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
> +{
> + struct tpm_chip *chip = container_of(rng, struct tpm_chip, tpm_hwrng);
> +
> + return tpm_get_random_dev(chip, data, max);
> +}
> +
> +static int tpm_add_hwrng(struct tpm_chip *chip)
> +{
> + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> + return 0;
Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
condition can be avoided.
> +
> + snprintf(chip->tpm_hwrng_name, sizeof(chip->tpm_hwrng_name),
> + "tpm-rng-%d", chip->dev_num);
> + chip->tpm_hwrng.name = chip->tpm_hwrng_name;
> + chip->tpm_hwrng.read = tpm_hwrng_read;
> + return hwrng_register(&chip->tpm_hwrng);
> +}
> +
> /*
> * tpm_chip_register() - create a character device for the TPM chip
> * @chip: TPM chip to use.
> @@ -419,11 +440,13 @@ int tpm_chip_register(struct tpm_chip *chip)
>
> tpm_add_ppi(chip);
>
> + rc = tpm_add_hwrng(chip);
> + if (rc)
> + goto out_ppi;
> +
> rc = tpm_add_char_device(chip);
> - if (rc) {
> - tpm_bios_log_teardown(chip);
> - return rc;
> - }
> + if (rc)
> + goto out_hwrng;
>
> rc = tpm_add_legacy_sysfs(chip);
> if (rc) {
> @@ -432,6 +455,14 @@ int tpm_chip_register(struct tpm_chip *chip)
> }
>
> return 0;
> +
> +out_hwrng:
> + if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> + hwrng_unregister(&chip->tpm_hwrng);
> +out_ppi:
> + tpm_bios_log_teardown(chip);
> +
> + return rc;
> }
> EXPORT_SYMBOL_GPL(tpm_chip_register);
>
> @@ -451,6 +482,8 @@ EXPORT_SYMBOL_GPL(tpm_chip_register);
> void tpm_chip_unregister(struct tpm_chip *chip)
> {
> tpm_del_legacy_sysfs(chip);
> + if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> + hwrng_unregister(&chip->tpm_hwrng);
> tpm_bios_log_teardown(chip);
> if (chip->flags & TPM_CHIP_FLAG_TPM2)
> cdev_device_del(&chip->cdevs, &chip->devs);
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 1d6729be4cd637..310de288549818 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -1194,9 +1194,8 @@ static const struct tpm_input_header tpm_getrandom_header = {
> *
> * Returns < 0 on error and the number of bytes read on success
> */
> -int tpm_get_random(u32 chip_num, u8 *out, size_t max)
> +int tpm_get_random_dev(struct tpm_chip *chip, u8 *out, size_t max)
> {
> - struct tpm_chip *chip;
> struct tpm_cmd_t tpm_cmd;
> u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA), rlength;
> int err, total = 0, retries = 5;
> @@ -1205,15 +1204,8 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
> if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
> return -EINVAL;
>
> - chip = tpm_chip_find_get(chip_num);
> - if (chip == NULL)
> - return -ENODEV;
> -
> - if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> - err = tpm2_get_random(chip, out, max);
> - tpm_put_ops(chip);
> - return err;
> - }
> + if (chip->flags & TPM_CHIP_FLAG_TPM2)
> + return tpm2_get_random(chip, out, max);
>
> do {
> tpm_cmd.header.in = tpm_getrandom_header;
> @@ -1231,10 +1223,9 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
>
> rlength = be32_to_cpu(tpm_cmd.header.out.length);
> if (rlength < offsetof(struct tpm_getrandom_out, rng_data) +
> - recd) {
> - total = -EFAULT;
> - break;
> - }
> + recd)
> + return -EFAULT;
> +
> memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd);
>
> dest += recd;
> @@ -1242,9 +1233,23 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
> num_bytes -= recd;
> } while (retries-- && total < max);
>
> - tpm_put_ops(chip);
> return total ? total : -EIO;
> }
> +
> +int tpm_get_random(u32 chip_num, u8 *out, size_t max)
> +{
> + int rc;
> + struct tpm_chip *chip;
> +
> + chip = tpm_chip_find_get(chip_num);
> + if (chip == NULL)
> + return -ENODEV;
> +
> + rc = tpm_get_random_dev(chip, out, max);
> +
> + tpm_put_ops(chip);
> + return rc;
> +}
> EXPORT_SYMBOL_GPL(tpm_get_random);
>
> /**
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 2d5466a72e40f8..0e41e044d81be2 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -26,6 +26,7 @@
> #include <linux/module.h>
> #include <linux/delay.h>
> #include <linux/fs.h>
> +#include <linux/hw_random.h>
> #include <linux/mutex.h>
> #include <linux/sched.h>
> #include <linux/platform_device.h>
> @@ -210,6 +211,9 @@ struct tpm_chip {
> int dev_num; /* /dev/tpm# */
> unsigned long is_open; /* only one allowed */
>
> + char tpm_hwrng_name[64];
> + struct hwrng tpm_hwrng;
> +
Can this also be put inside the #ifdef?
> struct mutex tpm_mutex; /* tpm is processing */
>
> unsigned long timeout_a; /* jiffies */
> @@ -548,6 +552,7 @@ void tpm_chip_unregister(struct tpm_chip *chip);
> void tpm_sysfs_add_device(struct tpm_chip *chip);
>
> int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
> +int tpm_get_random_dev(struct tpm_chip *chip, u8 *out, size_t max);
>
> #ifdef CONFIG_ACPI
> extern void tpm_add_ppi(struct tpm_chip *chip);
> --
> 2.7.4
>
Regards,
PrasannaKumar
On Wed, Oct 25, 2017 at 08:15:09PM +0530, PrasannaKumar Muralidharan
wrote:
> > +static int tpm_add_hwrng(struct tpm_chip *chip)
> > +{
> > + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> > + return 0;
>
> Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
> condition can be avoided.
Generally speaking IS_ENABLED is prefered over #ifdef as it reduces the
set of compilation combinations.
Jason
Hi Jason,
On 25 October 2017 at 20:48, Jason Gunthorpe
<[email protected]> wrote:
> On Wed, Oct 25, 2017 at 08:15:09PM +0530, PrasannaKumar Muralidharan
> wrote:
>
>> > +static int tpm_add_hwrng(struct tpm_chip *chip)
>> > +{
>> > + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
>> > + return 0;
>>
>> Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
>> condition can be avoided.
>
> Generally speaking IS_ENABLED is prefered over #ifdef as it reduces the
> set of compilation combinations.
Oh okay. No issues then.
Regards,
PrasannaKumar
On Wed, Oct 25, 2017 at 08:15:09PM +0530, PrasannaKumar Muralidharan wrote:
> > + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> > + return 0;
>
> Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
> condition can be avoided.
Nope. There is no reason to avoid the if-condition. Compiler will take
care of it. IS_ENABLED() macro is available just for the purpose Jason
is using it.
> > + char tpm_hwrng_name[64];
> > + struct hwrng tpm_hwrng;
> > +
>
> Can this also be put inside the #ifdef?
Yes. It should be inside #ifdef.
/Jarkko
On Wed, Oct 25, 2017 at 08:58:17PM +0200, Jarkko Sakkinen wrote:
> On Wed, Oct 25, 2017 at 08:15:09PM +0530, PrasannaKumar Muralidharan wrote:
> > > + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> > > + return 0;
> >
> > Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
> > condition can be avoided.
>
> Nope. There is no reason to avoid the if-condition. Compiler will take
> care of it. IS_ENABLED() macro is available just for the purpose Jason
> is using it.
>
> > > + char tpm_hwrng_name[64];
> > > + struct hwrng tpm_hwrng;
> > > +
> >
> > Can this also be put inside the #ifdef?
>
> Yes. It should be inside #ifdef.
Then we need #idefs in the .c code, IS_ENABLED is not enough :\ I
don't think the few bytes matters enough to bother.
Jason
On Wed, Oct 25, 2017 at 01:37:07PM -0600, Jason Gunthorpe wrote:
> On Wed, Oct 25, 2017 at 08:58:17PM +0200, Jarkko Sakkinen wrote:
> > On Wed, Oct 25, 2017 at 08:15:09PM +0530, PrasannaKumar Muralidharan wrote:
> > > > + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
> > > > + return 0;
> > >
> > > Can #ifndef CONFIG_HW_RANDOM_TPM be used instead? That way an if
> > > condition can be avoided.
> >
> > Nope. There is no reason to avoid the if-condition. Compiler will take
> > care of it. IS_ENABLED() macro is available just for the purpose Jason
> > is using it.
> >
> > > > + char tpm_hwrng_name[64];
> > > > + struct hwrng tpm_hwrng;
> > > > +
> > >
> > > Can this also be put inside the #ifdef?
> >
> > Yes. It should be inside #ifdef.
>
> Then we need #idefs in the .c code, IS_ENABLED is not enough :\ I
> don't think the few bytes matters enough to bother.
>
> Jason
I'll buy that!
A minor tidbit: could the tpm_ prefix removed from those fields?
/Jarkko
On Wed, Oct 25, 2017 at 10:00:30PM +0200, Jarkko Sakkinen wrote:
> A minor tidbit: could the tpm_ prefix removed from those fields?
Yes, in v2
I will send v2 when you land your rework patch as this will depend on it.
Jason